Signature: add SignatureNonce and Timestamp

Change-Id: Ie906c44076ed2c29e0574c13fabed397d102a6ce
Refs: #4599
diff --git a/changelog.rst b/changelog.rst
index 078b694..1793192 100644
--- a/changelog.rst
+++ b/changelog.rst
@@ -18,6 +18,7 @@
   + Make ``MetaInfo`` and ``Content`` elements optional
   + Change semantics of omitted (or set to zero) ``FreshnessPeriod`` element: it cannot be used to satisfy
     Interests with ``MustBeFresh``
+  + Add optional ``SignatureNonce`` and ``Timestamp`` elements to ``SignatureInfo``
 
 - **Name**